In the daily life, folding sliding doors are installed in quite many places, for example, in wardrobes, storage trunk, shoes cabinet and so on. It is mainly because the structure of such sliding doors is simple, the weight of the door is light and it is less space occupational when the door is opened and closed. Please refer to FIGS. 1 and 2, which show the structure of a conventional sliding door, it is mainly comprised of a track 1, a first door panel 2 and a second door panel 3 which are both equipped underneath the track 1. The first door panel 2 is adjacently hinged to the second door panel 3. The top of the outer flank of the first door panel 2 is pivotally linked to the track 1. A pulley 4 is located at the top of the outer flank of the second door panel 3, such pulley 4 can be rolled along the track 1 towards the direction of the first door panel 2. Users may push the second door panel 3 towards the first door panel 2, the pivotal portion between the first door panel 2 and the second door panel 3 is then folded causing the second door panel 3 to lean against the first door panel 2, thus the first door panel 2 and the second door panel 3 will form a superposition at one side to allow the door opened. When closing the door, users have to pull the second door panel 3 back to its original position, so that the first door panel 2 and the second door panel 3 can be horizontally adjacent to each other. It is not ideal for users to always have to manually push the second door panel 3 to open the door and to pull back the second door panel 3 when closing. And users will eventually forget to pull back the second door panel 3 to its original position, causing the chance of door closure is not frequent even the folding sliding door is installed, gradually formed nominally.